Oxygen concentrators have become used extensively for supplying oxygen-enriched gas to respiratory patients, particularly those requiring relatively high oxygen concentrations in a breathable gaseous mixture over extended periods of time. Because oxygen concentrators deliver a breathable gas of between about 80-95% oxygen from atmospheric air, thereby eliminating the requirement of bottled gas, oxygen cylinders, and the like, they have found substantial appeal especially in the home care field.
In my aforesaid prior patent there is described an improved oxygen concentrator which monitors the concentration of the gaseous mixture produced and delivered by the apparatus. In one embodiment a microprocessor monitors the concentration of oxygen in the gaseous mixture produced, and in response adjusts the timing cycle of a valve which directs atmospheric air to the molecular sieve beds from the compressor.
As reliable as oxygen concentrators have become, often power consumption requirements are relatively high. Because of constantly increasing costs of electricity, where such concentrators are required to operate over extended periods of time, as they often are, costs of operation can be substantial, even to the point of otherwise offsetting the convenience of such devices. It is to an improved oxygen concentrator apparatus which automatically adjusts itself for lower power consumption when less than the full operating capacity of the apparatus is required that the present invention is directed.